Species Interactions and Community Ecology Overview

Community ecologists

The factors that influence biodiversity and the composition of communities.

Functional roles

No two species that live in the same location are functionally identical: every species has a unique niche.

Invasive species

Invasive species introduce competition into environments which leads to a significant negative impact on the native species.

Zebra mussels introduction

Contaminated ballast water discharged from European ships.

Zebra mussels spread

Within 6 years, the mussels had spread to the Mississippi watershed and into 19 states. They are now found in 30 states in America.

Biological and economic impacts of zebra mussels

Zebra Mussels filter algae, needed by zooplankton, native mussels, and other native species, from the water, and they attach to debilitate native mussels. They also cost power plants and industrial facilities on the Great Lakes about 3 million dollars a year.

Intraspecific competition

Intraspecific competition occurs between members of the same species.

Interspecific competition

Interspecific competition occurs between members of different species.

Competitive exclusion principle

No two functionally identical species coexist in the same location.

Fundamental niche

The fundamental niche of a species is constrained by interactions with competitors to what is called its realized niche.

Resource partitioning consequence

When a resource is partitioned, fewer members of a species can be supported.

Predation

Another type of species interaction where individuals of one species kill and consume individuals of another species.

Arms race

An arms race is where predators impose selection on prey to avoid being killed and defense adaptations of prey impose selection on predators to be more efficient killers.

Resilience in ecological communities

If a community returns to its original state after a disturbance, it is said to be resilient.

Resistance in ecological communities

If a community remains stable after a disturbance, it is said to be resistant.

Community complexity

Very complex and interlinked trophic communities tend to be resistant and resilient to perturbations.

Functional redundancy

When different species in a community are functionally redundant, they are more likely to withstand disturbances that result in the diminishing of certain species.

Keystone species

A species with an impact that effectively defines an ecosystem and without which the ecosystem might fail to exist.

Keystone species trophic levels

No, they can be found at any trophic levels.

Ecosystem engineer

Living things in an environment that drastically alter the physical environment. Such as beavers- building dams.

Trophic cascade

When the removal of a top predator keystone species may cause a dramatic shift of abundance or composition of species at lower levels.

Community regime shift

When the removal of a keystone species results in a community that no longer resembles the original one. This can be because of climate change or the introduction of an invasive species.

No-analog community

Communities different from any current communities.

Communities

Communities different from any current communities.

Primary cause of formation or dissolution

They are linked to climates that are different from any current communities. Their dissolution is present with the uprising of climate change.

Primary succession

Extraordinary disturbances may eliminate all or most of the species in a community and initiate a sequence of changes called primary succession.

Example of primary succession

The eruption of Mount Saint Helens in Washington.

Beginning of primary succession

Primary succession begins with the colonization of bare rock of pioneer species, like grasses and forbes, which can spread over long distances and are adapted for rapid growth.

Lichen

Lichens are fungi that form from a mutualistic symbiotic partnership.

Role of lichens

They secrete acids that break down rock which initiates the formation of soil.

Climax community

When pioneer species are ultimately out competed by shade tolerant hardwood trees, which form a more stable community- A climax community.

Aims of restoration ecologists

They use information on succession to devise methods that restore the functionality of an ecosystem. They aim to restore the ecosystem to its state before it was disturbed by humans.

Purpose of canals in Florida

These canals were constructed in order to drain the Everglades of water for agricultural development, flood protection, and for a source of clean water.

Everglades restoration project

Everglades restoration is a multi-billion dollar state and federal partnership to restore the flow of clean freshwater from Lake Okeechobee to the remnant Everglades and ensure flood protection and a clean water supply for millions of citizens.

Invasive plant species in Ohio

There are over 500 invasive plant species in Ohio.

Invasive plant threatening native communities in Ohio

Garlic Mustard.

Primary vector for invasive species

Humans.

Global species diversity pattern

It is highest near the equator and lowest near the poles.

Similarity of global diversity patterns for plants and animals

Yes, these are generally the same.

Explanation for global patterns in biodiversity

Something about the tropical environments allow for more species diversity.

Age of the tropics

Tropical environments are older than the more temperate environments.

Single explanation for global patterns of species diversity

No.

Biodiversity

The variation among organisms and ecological systems at all spatial levels.

Feature of diversity relevant for populations

Populations with little genetic diversity are more vulnerable to environmental change, as they may lack variants that are able to function under new conditions.

Most speciose group of organisms

Animals.

Most speciose group of animals

Insects.

Most speciose group of vertebrates

Fish.

Ecosystem diversity

The number of ecosystems, communities, or habitats in some defined area.

Species richness

The number of species within a defined area.

Weaknesses of species richness as a measure of diversity

It does not take into account the rareness of each species or how populated the species is.

Relative abundance of a species

The proportional representation of a species in a community or a sampled area.

Rank-abundance plot

A rank-abundance plot tells us about species evenness.

Relative abundance

The relative abundance of the most abundant species is plotted first, followed by the second most abundant and so on.

Species evenness

These plots reveal the species evenness within a community or sample.

Rank-abundance plots

Rank-abundance plots reveal that ecological systems are typically composed of a few highly abundant species and many rare ones.

Species richness

The number of species in a region generally increases with the size of the area that is sampled.

Local diversity

Number of species in one habitat.

Regional diversity

Number of species in all habitats of a geographical area.

Species turnover

Difference in species.

Beta diversity

Difference in species from one habitat to another.

Sorenson Index

The further apart the species are from each other geographically, the less alike they are.

Latitudinal gradients

The consistency of latitudinal gradients in diversity suggests that species diversity depends on processes that act uniformly around the ground.

Structural complexity

The structural complexity of vegetation may be more important than large-scale productivity with regard to species richness.

Robert MacArthur

He anticipated the importance of structural complexity for species richness.

Species richness on islands

Species richness on islands is typically low.

Factors determining species richness on islands

The size of the island and the distance from the mainland.

Benefits of biodiversity

Water and air purification, the promotion of waste decay, stabilization of climate, crop and livestock security, cultural and aesthetic benefits, pollination of crops, reduced risk of disease spread.

Pharmaceuticals from wild plants

About 50% of pharmaceuticals used today are derived from wild plant species.

Diversity and disease control

There is generally a reduced risk of disease spread with an increase of host diversity; biodiversity protects organisms including humans from transmission of infectious diseases.

Pollutant removal and algae diversity

Biologically diverse streams clear pollutants from water better than less rich waterways. Streams with more diverse populations of algae are better biofilters.

Decomposition and diversity of decomposers

Leaves of different plant species have distinct chemical and physical properties that are decomposed by diverse communities of invertebrate and microbes.

Preservation of wild plant diversity

Populations of wild plants contain genetic diversity not found in their cultivated varieties, which can be used to breed new varieties capable of adaptation to climate change and other environmental stresses.

Ecotourism profitability

Yes, visitors to natural areas support local businesses, hire locals as guides and support park employees. In Tanzania, ecotourism is responsible for a quarter of all foreign currency that enters the economy.

Ecotourism benefits

No, ecotourism is a financial benefit to all countries who partake in it.

Threats to biodiversity

Habitat loss or degradation, pollution, human population growth, illegal trade of wildlife products, invasive species, climate change.

Primary cause of biodiversity loss

Not specified in the notes.

Habitat loss or degradation

One of the six main threats to biodiversity.

Pollution

One of the six main threats to biodiversity.

Human population growth

One of the six main threats to biodiversity.

Illegal trade of wildlife products

One of the six main threats to biodiversity.

Invasive species

One of the six main threats to biodiversity.

Climate change

One of the six main threats to biodiversity.

Primary cause of biodiversity loss

Habitat loss or degradation.

Habitat fragmentation

Fragmentation of habitat creates small usable areas and gaps that some species cannot cross.

Human alterations to ecosystems

Favor generalists, which can shift resource use in response to environmental change, and harm specialists, which rely on stable habitats.

Characteristics of species coping with disturbances

Organisms that benefit from human disturbances tend to be widespread, small, on the fast end of the slow-fast life history continuum, and lower on the food chain.

Forests as a buffer against climate change

Each year, forests absorb about 7.6 gigatons of CO2 from the atmosphere, roughly 18 percent of all human-caused carbon emissions.

Forest loss per year

About 100,000 square kilometers of forest, an area the size of Portugal, is destroyed.

Forest loss per second

The area the size of a soccer field is destroyed.

Impact of air pollution on biodiversity

Air pollution degrades forests and affects the climate.

Impact of water pollution on biodiversity

Water pollution directly harms fish and amphibians.

Agricultural runoff

Alters the food webs of aquatic ecosystems.

Persistent pollutants

Like heavy metals, directly poison humans and animals.

Noise and light pollution

Influence the behavior and habitat use of animals.

Plastic in the ocean

Kills marine animals.

Human population growth and resource exploitation

Imposes higher exploitation rates.

Overexploitation

The populations cannot be sustained.

Proportion of oceanic fisheries overexploited

About 30 percent.

Proportion of oceanic fisheries fully exploited

More than half.

Cause of declines in elephant populations

The illegal trade of animal products and poaching.